This invention relates to magnetometers in general and more particularly to a high sensity gradient magnetometer which is operable at all angles with respect to the magnetic field being measured.
A high sensitivity microgradient magnetometer utilizing two interconnected magnetic resonance spin generators on a common base is described in U.S. Pat. No. 3,863,144. In the device disclosed therein, magnetic resonance cells are pumped by a common pumping means which is divided by beam splitters. A seperate readout lamp is utilized, coupled through a beam divider, to detect differences, caused by gradients in the scalar magnitude of the earth's magnetic field.
The major disadvantage of a magnetometer such as that disclosed in the aforementioned patent is that it is not operable for all orientations relative to the magnetic field being measured. Typically, a magnetometer of this nature will be mounted in an aircraft for use in detecting bodies on the surface of the earth which distort the earth's magnetic field. A typical example is the use in marine vessel detection or use in prospecting to find mineral deposits. To be a more useful device in such an application, the magnetometer should operate over all angles, that is, on all headings and at all magnetic latitudes. However, a magnetometer of this nature is not sensitive if the magnetic field lies along the direction of the readout beams, and may be in error when the magnetic field does not lie along the direction of the pump beams.
Thus, the need for an all-angle gradient magnetometer of this nature becomes evident.